Long chain alkoxy diamines



United States Patent 3,023,243 LONG CHAIN ALKOXY DIAMINES Harry A. Stansbury, Jr., South Charleston, and Howard R. Guest, Charleston, W. Va., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filed Oct. 19, 1956, Ser. No. 616,936 3 Claims. (Cl. 260- 584) This invention pertains to a new series of long chain alkoxy-substituted diamines, in which the amino groups are in the terminal positions, and to a method for making them. In this series of compounds, the terminal amino groups are separated by an odd number of carbon atoms, which is at least seven, and the number of alkoxy substituents is related to the chain length of the diamines by the relationship,

where N is the number of alkoxy substituents, and n is the odd number of carbon atoms in the chain.

Long chain diamines in which the terminal amino groups are separated by an odd number of carbon atoms have heretofore been available only in low yields by an expensive synthesis. For example, l,7-heptanediamine has been prepared by passing the lactone of gamma-hydroxypimelic acid and ammonia over a dehydrating catalyst at 325 C. to 550 C., and catalytically hydrogenating the so-formed heptenedinitrile. The present invention not only includes a commercially attractive method for making long chain primary diamines, but it also provides a novel series of alkoxy-substituted diamines. Such alkoXy-substituted diamines are of particular value in making polyamides, wherein the alkoxy substituents contribute lower melting points and increased compatibility with synthetic resins. The process of the present invention also permits the preparation of N,N'-derivatives of the alkoxy diamines.

The basic raw materials utilized in the new synthesis of long-chain alkoXy-substituted diamines are acrolein and vinyl alkyl ethers, both of which are available commercially at reasonable costs. In the first step, acrolein is condensed in a known manner with aivinyl alkyl ether to yield a 2-alkoXy-3,4-dihydro-2H-pyran. This pyran is reacted with an alkanol in such a manner as to open the pyran ring and form 1,1,5,5-tetra-alkoxypentanes or glutaraldehyde cliacetals. These diacetals are then reacted with at least one mole of an alkyl vinyl ether to form diacetals of alkoXy-substituted alpha, omega dialdehydes having at least one alkoXy-substituentin the chain and at least seven carbon atoms in the chain. The chain length of these dialdehyde diacetals increases in increments of two carbon atoms, depending on the number of moles of vinyl alkyl ether reacted, and they contain an added alkoxy group for each increment of two carbon atoms in the chain. These alkoxy-sub'stituted dialdehyde diacetals are then hydrolyzed to the corresponding dialdehydes, which are then aminated to form the long chain alkoXy-substituted diamines of this invention.

The various steps of the synthesis are illustrated below:

(I) /Cgl HO OH: CHz:CHCHO+CHz=CHOB ,H

HO OH 0 R Acrolein Vinyl alkyl ether O 2-alkoxy-3,4-dihydro-2H-pyran 0 H, 0 H2 HO OH; H20 CH2 2ROH .II +ROH- J3 HO /OHOR ROH CHOR Alkanol 2-alkoxv-3,4-di- Alkanol 2-6- dialkoxytetrahyhydrO-ZH-pyran dropyran (RO)zCHCH2CHzCH2CH(OR)z H2O 1,1,5,5-tetraalkoxypentane Water (III) (RO)ZCHOHZCH2CHZOH(O R)z+x(CH2=CHO R)'- 1,1,5,5-tetraalkoxypentane Vinyl alkyl ether Acetals of alkoxy-substituted alpha, omega dialdehydes Acetals ol alkoxy-substituted alpha-omega Water dialdehydes 0 R 0 011CHzCHzCH2(HOH2)ICH=O+4ROH Alkoxy-s ubstituted Alkauol dialdehydes (I) R /R O=CHCHOH2OH2(CHCH;)zCH=O 2H; +2HN Alkoxy-substituted dialdehydes Hydrogen Ammonia or amine R O R R NOH2CH2CH2CH2(CHCH2)IOH2N 2H O RI! \RI) Alkoxy-substit uted terminal diamines Water R and R" are hydrogen or hydrocarbyl radicals.

It will be noted that overall synthesis involves the addition of vinyl alkyl ethers, stepwise, first to a three carbon atom compound, acrolein, and then the resulting five carbon atom compound, the glutaraldehyde acetals. Furthen more, the process is regenerative, in that the alcohol used in step II is recovered in the hydrolysis step IV. As all the steps may be carried out with good eflicien'cies, the overall process is an effective one for converting acrolein and vinyl alkyl ethers to long chain terminal diarnines andtheir N,N'-substitution products.

The preferred class of alkoXy-substit'uted terminal diamines of this invention are represented by the formula:

N0112cmornonndnonmcnm where x has a value from 1 to 10, depending on the number of moles of vinyl alkyl ether reacted with the glutaraldehyde diacetal in step III of the synthesis. In the above formula, R is an alkyl radical having from 1 to 8 carbon atoms, and may be the same or different throughout the chain, depending on whether a mixture of vinyl alkyl ethers is used in step III of the synthesis, and on whether the alkyl radical of the l,1,5,5-tetraa1koxypentane is the same as or different from the alkyl radical of the vinyl alkyl ether used in the reaction, and" R and R" are hydrogen or lower alkyl radicals, such as methyl, ethyl or butyl..

While it is possible to isolate definite compounds from the diamine mixtures of this invention, such as 3-ethoxy- 1,7-heptanediamine, the more valuable compositions will comprise mixtures of such diamines Where x has a value from 1.5 to 5.5.

' In such reactions of the vinyl alkyl ether with the 1,1,5,5-tetraalkoxypentane, it is desirable to use an acidic catalyst. Suitable catalyst include boron trifluoride and acid treated clays. The reaction temperatures may be from about C. to about 100 C. with 30 C. to 60 C. being the preferred range. The corresponding reaction processes may vary from about 5 to 150 p.s.i.a. With pressures of p.s.i.a. to 50 p.s.i.a. being preferred.

The hydrolysis of the alkoxy-substituted acetals to the alkoxy-substituted dialdehydes, shown in step IV of the synthesis, is best accomplished at a pH of 1 to 5, with a pH of 2 to 3 being preferred. The hydrolysis temperatures are in the range of C. to 150 C. with temperatures of 80 C. to 100 C. being preferred. Depending on the temperature, the reaction time may vary from a few minutes to as long as 20 hours. The amount of water used for the hydrolysis may be varied from about 10% of the weight of the acetals to about 500%, with about 100% being preferred.

The reductive amination of the alkoxy-substituted dialdehydes to the alkoxydiamines proceeds best under pressure and at an elevated temperature. The hydrogenation temperature may be from 30 C. to 180 C. at pressures from 100 p.s.i.a. to 2000 p.s.i.a. A hydrogenation catalyst, such as Raney nickel or cobalt, is usually employed.

Among the amines useful in such reductive amination are methyl amine, ethyl amine, diethyl amine, butyl amine, dibutyl amine, hexyl amine, Z-ethylhexylamine, di(2-ethylhexyl) amine, ethanolamine, isopropanolamine, N-(Z-aminoethyl) ethanolamine and aniline.

. The alkoxy-substituted terminal diamines of this invention are extremely valuable intermediates because the alkoxy-substituted carbon chains between the terminal amino groups can be varied from a minimum of seven carbon atoms to as long as twenty-seven carbon atoms. Thus, a proper balance can be maintained in the final derivative between the properties contributed by the alkoxy-substituted carbon chain and the functional group employed to combine with the terminal amino groups. Thus, the diamines may form a series of polyarnides with dibasic acids.

Depending on the chain length of the diamine, which may be 7, 9, 11 or higher, the ratio of amine chain length to acid chain length can readily be varied to control the softening point of the polyamides. The resulting polyamides are useful for fibers, films and molding compositions.

The diamines of this invention are useful hardeners for epoxide resins, serving as cross-linking agents because of the reactivity of the primary or secondary amino groups with the epoxy groups of the resins. The tertiary diamine of this invention, for instance, those diamines of the above formula where both R and R are alkyl, serve as catalysts for the polymerization of the epoxide resins through reaction of the epoxy groups. Epoxy resins mixed with the diamines of this invention have a longer pot life than epoxy resins mixed with other aliphatlc polyamines, since the long chains between the amine groups reduces the reactivity of the diamines as hardeners.

Among the polyepoxides suitable for reaction with the diamines of this invention, are the polyglycidyl ethers formed by reacting epichlorhydrin with polyphenols, such as 2,2-bis(hydroxyphenyl)propane (Bisphenol A), 1,1,3- tris(hydroxyphenyl)propane and 1,1,2,2-tetra(hydroxyphenyl)ethane. Other diepoxides which may be reacted with the diamines to form polymers include butadiene diepoxide and vinylcyclohexane diepoxide.

In such hardening and polymerization reactions with diepoxide, the alkoxy-substituted diamines provide versatility as cross-linking agents because the chain length of the diamine can be varied.

Certain of the diamine derivatives, such as the N,N'- diethyl derivative, are useful repellents for house flies.

The various steps of the synthesis of the diamines from acrolein and vinyl alkyl ethers are illustrated in the examples to follow, the first step of the synthesis, the formation of the 2-a1koxy-3,4-dihydro-2H-pyrans, being shown in U.S. Patent No. 2,514,168.

PREPARATION OF 1,1,5,5-TETRAALKOXYOXY- v PENTANE-STEP H 2-ethoxy-3,4-dihydro- ZH-pyran Ethanol 1120 CH; CzHsOCE I 3HOC2Hs 2, G-diethoxytetrahydropyran (C2H50)zCHCHzCHgCH2CH (0 01115) z-l-HaO 1,1,5,5-tetraethoxypentane Water Example 1 Example 2 A mixture of 3.68 grams of 96% sulfuric acid (0.075 equivalent), 1918 grams of anhydrous ethanol (43 moles) and 748 grams of 2,6-diethoxy-tetrahydropyran (4.3 moles) was refluxed for 2 hours. After 8.2 grams of anhydrous sodium acetate were added to neutralize the catalyst, the mixture was fractionated under reduced pressure to obtain 1,1,5,5-tetraethoxypentane in 52% yield and 98% efliciency based on 2,6-diethoxytetrahydropyran.

CONDENSATION OF 1,1,5,5-TETRAALKOXYPEN- TANE WITH VINYL ALKYL ETHER-STEP III (CzH5O)2CHCHzC-H2CH2CH(O CzH5)2+CH2=CHO CzH5 1,1,5,5,-tetraethoxypentane Ethyl vinyl ether (CzH50);;CHCH2CH2CHzCHCHzCH(O (J2EE): 1,1,3,7,7-pentaethoxyheptane O CzHs 0 C2115 O C2115 O CzHs (CQH50)2CHCHgCHCH2CHgCH2CHCHzCH(O CzHsh 1,1,3,7,9,9-hexaethoxynonane Example 3 A mixture of 124 grams of 1,1,5,5-tetraethoxypentane (0.5 mole) and 52 grams of Superfiltrol (an acidtreated clay sold by the Filtrol Corporation) was stirred at 25 C.-30 C. While a solution of 144 grams of ethyl vinyl ether (2 moles) in 248 grams of 1,1,5 ,5-tetraethoxypentane (1 mole) was fed over a period of 40 minutes. After a reaction period of half an hour at 25 C., the mixture was filtered. The filtrate Was mixed with 5 grams Equivalent Sp. g. Fraction Bolling range weight as 20l20 n 30/D acetal 121 132 C./1 mm. 152.2 0. 930 1. 4242 132-154 O./1 mm. 177.0 0.938 1. 4273 154210 O./1 mm. 191.0 0.958 1.4384

Fraction 1 was 1,1,3,7,7-pentaethoxyheptane, for which the theoretical equivalent weight as acetal is 160. Fraction 2 was a mid-cut, while fraction 3 was a mixture of 1,1,3,5,9,9-hexaethoxynonane and the isomeric 1,1,3,- 7,9,9-hexaethoxynonane, for which the theoretical equivalent weight is 196. The yield of 1,1,3,7,7-pentaethoxyheptane was 13%, while the yield of hexaethoxynonane was 25% based on the ethyl vinyl ether.

Example 4 A mixture of 1.6 grams of 47% boron trifiuoride in diethyl ether (0.033 equivalent) and 303 grams of 1,1,5,5 tetraethoxypentane (1.22 mole) was stirred at 35-40 C. while a solution of 432 grams of ethyl vinyl ether (6 moles) in 744 grams of 1,1,5,5-tetraethoxypentane (3 moles) was fed over a period of one hour and forty minutes. After a reaction period of 45 minutes at 35 C., 5.3 grams of powdered anhydrous sodium carbonate (0.1 equivalent) were added and the mixture was stirred for 2 hours at 30 C. The mixture was filtered and the filtrate was flash-distilled (in the presence of 5 grams of sodium carbonate) to a kettle temperature of 248 C. at a reduced pressure of 4 mm. The residue (437 grams) had an equivalent weight of 344 by acetal analysis.

The flash-distilled product fraction (514 grams) was fractionated to isolate the following fractions:

Equivalent Sog. Fraction Boiling range weight as 20/20" 11 30/D acetal 143153 C./3 mm 166. 5 0.928 1. 4258 153-163 J3 mm- 186.0 0.933 1. 4287 163175 C./3 mrn 201.0 0. 937 1.4308 175-212 C./3 mm 221.0 0.943 1. 4350 Fraction 1 was 1,1,3,7,7-pentaethoxyheptane, fraction 2 was a mid-cut, fraction 3 was a mixture of 1,1,3,5,9,9- 'hexaethoxynonane and the isomeric 1,1,3,7,9,9-hexaethoxynonane and fraction 4 was mostly the latter isomeric mixture. The yield of 1,1,3,7,7-pentaethoxyheptane was 10% and the yield of hexaethoxynonane was 15% based on 1,1,5 ,S-tetraethoxypentane.

PREPARATION OF ALKOXY SUBSTITUTED DIALDEHYDES-STEP IV (QzHgO) 20 CH OH2CH2CHZCH (0 0 151 1+22CH2=QHO CgH5- 1,1,5,5-tetraethoxypentane Ethyl vinyl ether i (C2HO 2CHCH1CH2CH2 CHCH; xCH(OC H Polyethoxytetraethyl acetals Ac d (0 02115 O=CHCH2CH2CH2 CHOHZ zCH=O+4C H OH Pblyethoxydialdehydes Ethanol Example 5 erage chain length was about 9 carbon atoms. The yield and efficiency were 40% and respectively based on tetraethoxypentane. The yield and efficiency based on ethyl vinyl ether were 82% and 90%, respectively.

The above polyethoxytetraethyl acetal (1724 grams, 8.72 equivalents) was mixed with an equal weight of water and 33 ml. of 0.5 N sulfuric acid were added to reduce the pH to 3. The mixture was distilled with reflux for 5.5 hours until no more ethanol was being generated. Analysis of the aqueous ethanol distillate (967 \grams) showed that it was 83% ethanol, which corresponded to a quantitative yield of ethanol based on the acetal charged. The residue was separated into 803 grams of oil layer which contained 4.37 equivalents of aldehyde and 1686 grams of water layer which contained 3.18 equivalents of aldehyde by analysis. The yield of dialdehydes based on the tetraethyl acetals was 86.6%.

Example 6 A mixture of 744 grams of 1,1,5,5-tetraethoxypentane (3 moles) and 4.4 grams of 43% boron trifluoride in diethyl ether was stirred at 50 C. while a solution of 1296 grams of ethyl vinyl ether (18 moles) in 1488 grams of 1,l,5,5-tetraethoxypentane (6 moles) was fed over a period of 2.1 hours. The catalyst was neutralized by the addition of gaseous anhydrous ammonia. The mixture was filtered and stripped to a kettle temperature of C. at a reduced pressure of 3 mm. to obtain 2537 grams of polyethoxytetraethyl acetals as a residue product having it 30/D 1.4340, sp. g. 20/20 0.944, 214 equivalent weight by acetal analysis. The yield and efiiciency based on vinyl ether were 82% and 90%, respectively. The yield and efiiciency based on 1,1,5,5tetraethoxypentane were 66% and 90%, respectively.

The polyethoxytetraethyl acetal (2530 grams, 2L4 equivalent weight) 11.82 equivalents, x=2.5 in the general formula) was distilled with 1250 ml. of water containing 25 ml. of 0.5 N sulfuric acid to reduce the pH to 2. After 8 'hours, 1313 grams of aqueous ethanol had been distilled and no more ethanol was being formed. The residue was separated into 1653 grams of oil layer which contained 10.8 equivalents of aldehyde and 801 grams of aqueous layer which contained 0.662 equivalents of aldehyde by analysis. The yield of dialdehydes based on the acetals was 97%.

Example 7 A mixture of 1948 grams of polyethoxytetraethyl acetals (192 equivalent weight, x=2.03, 10.15 equivalents) was distilled with 1948 ml. of water containing 30 ml. of 0.5 N sulfuric acid to reduce the pH to 3. After 6 hours, 1199 grams of distillate containing 20.6 moles of ethanol had been collected and no more ethanol was being liberated. The residue was separated into 914 grams of oil layer which contained 6.12 equivalents of aldehyde and 1758 grams of aqueous layer containing 3.30 equivalents of aldehyde by analysis. The yield of dialdehydes was 93% based on the acetals.

PREPARATION OF POLYETHOXYDIAMINES MINAL DIAMINES-STEP V (OCzHs /R O=CHCH2CH2CHz CHCH: xCH=O 2H2 2NH Polyethoxydialdehydes Hydrogen Ammonia or amine R f O O Hs R NomomoHAoHom 10H, R R

Polyethoxydiamines Twenty moles of 64.7% aqueous ethylamine were E x amp l2 8 stirred at 20 C. while an aqueous mixture of polyethoxydialdehydes (1.1 equivalents, average of x in above for- (OCZHt mula was 2.5) were fed over a period of 40 minutes. The

O=CHCH2CH2OH2 onom eon=o 2H: 21am resulting solution was hydrogenated at a maximum term- Polyethoxydialdehydes Hydrogen Ammonia perature of 150 C. and 1000 p.s.i. The filtered mixture (002135 was stripped to a kettle temperature of 80 C./ mm. to

obtain a residue product having these properties: n 30/D ENOHZCHNHZCH FF ICHZNHZHHIO 1.4597, sp. g. 20/20 0.922, 162.7 equivalent weight by lyethoxydmmmcs Water 10 amine analysis (theory 169), 316.5 molecular weight by An aqueous mixture of polyethoxydialdehydes (2- the Menzies-Wright method (theory 33s ,9.1% N(theory equivalents in 818 grams of mixture) was mixed with 50 8.3%), 67.1% C (theory 67.5%), 11.2% H (theory grams of Raney nickel and 170 grams of anhydrous am- 12.4%), partially soluble in water. The yield was 95%. monia (10 moles) in a rocking-type of autoclave. After a reaction period of 10 minutes at 4045 C., hydrogen Example 11 was added to increase the pressure to 800 p.s.i.g. and the temperature wa raised to maximum of 148 C. over a period of 3.5 hours. The filtered mixture was stripped to a kettle temperature of 78 C./ 7 mm. to obtain a viscous residue product having these properties: n 30/D 1.4853,

(001115 OCHOHrCHzCH CHOHQ zCH0+2HrNGH2cHZNHCHQCH OHHHQ Polyethoxydialdehydes N-(2-aminoethyl)ethanolamine 7 PREPARATION OF POLYETHOXYDIAMINES The condensation product of the polyethoxydialdehydes and N-(2-aminoethyl)ethanolamine was hydrogenated to form amixture of the corresponding polyethoxytetraminediols having the general formula illustrated below.

0 0 11 H O OH OH NH CIKQOHQNHCHZOHICHZCH2 GHCHDzCENH CHZCHQNH CHQCH2OH+HQO Polyethoxytetraminediols sp. g. 28/20 0.994, 164 equivalent weight by analysis Twenty moles of N-(2 aminoethyl)ethanolarnine were for amine, 366 molecular weight by the Menzies-Wright stirred at C. while an aqueous mixture of polyethoxymethod, partially soluble in water. The yield of amine dialdehydes 1.1 equivalents of aldehyde contained, averwas 70% based on the dialdehyde. age of x in above formula was 2.5) was fed over a period The stripped residue product was distilled to obtain the of minutes. The resulting solution was hydrogenated fractions described below. in the presence of 3 percent Raney nickel to a tempera- Per- Fraction Boiling Prcs- Eq. wt. 2: Mol. Miscihle with n 30/D Sp. G. cent of range, 0. sure, wt. water? 20l20 still mm. charge 97-120 3 103 1.45 Yes 1.4776 0.938 11 120460 4 124 2.03 188 Yes 1. 4782 0. 964 14 160-193 4 136 2. 36 Partially 1. 4789 0.979 11 Residue N 33 Determined by analysis for amine.

( Calculated from the observed equivalent Weight.

( Dctermined by the Menzies-Wright method.

( Rotor temperature on the molecular still in which fraction 4 was distilled.

Example 9 ture of 150 C. and 1000 p.s.i.g. The filtered mixture was An aqueous mixture of polyethoxydialdehydes was p to kettle temperature of (.1/5 prepared in 95% yield by hydrolysis of the correspondmlxmre of pollifithoxytetrammedtols as a ing acetals having an average equivalent weight of 216.3, cous resldue prqduct havlpg these pfopemesz. n 30/1) which corresponds to x=2.63 in the general formula. 106-8 equlfalent Weight y amlne analysis (theory The dialdehyde mixture (309 gms. containing 1.38 equiva- 114) 2385 eqmvalent Welght hydroxyl analysls lents of aldehyde) was treated with 5 ml. of 2% NaOH (thliory 228) 426 molecular W i y the Menzles' to increase the pH to 5.5 and then charged to a rocking '55 Wright method (theory 456) mlsclble Wlth The autoclave along with 600 ml. of ethanol solvent and yleid was l The produc.t was llseful as an epoxy grams of Raney nickeL After 340 grams of anhydrous resin hardener, having both reactive amino and hydroxyl ammonia (20 moles) were added, the mixture was shaken groups at 34-38 C. for 10 minutes. Then hydrogen was added to a. maximum pressure of 1100 p.s.i.g. and the mixture 60 was heated to 150 C. over a period of an hour. The mixture was filtered and stripped to a kettle temperature of C./ 5 mm. to obtain 160 grams of a viscous residue product having n 30/D 1.4811 and 137 equivalent weight as determined by amine analysis. The yield was 85% 5 based on the aldehyde charged.

Example 12 The product of Example 10 was evaluated as an epoxy resin hardener. On mixing equivalent amounts of the diamine and the diglycidyl ether of Bisphenol A (2,2'-diphenylolpropane), a pot life of 67 minutes was obtained with a low degree of heat released. The total mass of the sample was 50 grams at an ambient temperature of 27 to 28 C.

Example 10 Test specimens of castings which were allowed to gel at 00235 room temperatures and then baked for two hours at oonomcmonidncHQmno 202mm, 2H1 70 C had followmg physlcal propemes:

Polyethoxydialdehydes Ethylamine Hydro en H di i 73 C v OCZHE Rockwell hardness-M 92.

Izodim act 0. Sit. C H NHCH3CH2CH2CH2 CHC 2) 2 z u-l- 2 l l Strength 1 700 i wldth NN"dlethylpmyethoxydiamines 75 Flexural modulus of elasticity"-.. 44x10 p.s.i.

9 What is claimed is: 1. A mixture of alkoxy-substituted diam-ines of the formul-awhere R is an alkyl radical having from 1 to 8 carbon atoms, R is a radical from the group consisting of hy- 2. A mixture of alkoxy-substituted alpha, omega primary diamines of the formula- 0R H NCH CHzCHQCH OHCH2 ICH1NHI where R is an alkyl radical having from 1 to 8 carbon atoms and x has an average value from 1.5 to 5.5.

3. Polyethoxytetraminediols of the formula- HO CHQCHINHCHaCHgNHCHzCHaCHqCH1 1HCHa)ICHQNHCH,CHQNHCI-IQCH;OH

drogen and an alkyl radical having from .1 to 4 carbon atoms and x has an average value from 1.5 to 5.5.

where x has an average value from 1.5 to 5.5.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Stevenson: Industrial and Engineering Chemistry, vol.

41, No. 9 (1949), page 1848.

Karrer: Organic Chemistry (1950), page 162. Migrdichian: Org. Synthesis, vol. I (1951), page 202. Coifman et al.: J. Am. Chem. Soc., vol 76 (1954), page 

1. A MIXTURE OF ALKOXY-SUBSTITUTED DIAMINES OF THE FORMULA-
 3. POLYETHOXYTETRAMINEDIOLS OF THE FORMULA 